In Heat
by ipreferwestside
Summary: Thanks to their inconsistent schedules, and his frequent travels, they've only seen each other a couple of times since they'd met on a case his team had consulted on. A Criminal Minds-inspired one shot. Complete.


**A/N: While I've designated this as a Castle fic, it does include some Criminal Minds characters. Knowledge of that show is not necessary to read this.**

* * *

"This better be a fucking emergency," she grumbles into the phone, silencing the obnoxious ringtone with a swipe of her thumb.

The offending caller chuckles, a low, throaty sound that has her face flushing and her blood boiling. "I can't call my girlfriend to greet her good morning?" he teases, and she can see him in her mind, likely sitting at his kitchen table, maybe his couch, drinking coffee. His second cup, probably.

The bastard.

She's usually the morning person between the two of them, but she'd been up for almost two straight days working two linked homicides that have her stumped. And it's - she groans when she checks the time - way too damn early to be conscious, especially after such a late night.

"Not when your girlfriend got two hours of sleep," she snaps. She instantly regrets it when he falls silent, and she mutters an apology, smiling despite herself when he accepts it without hesitation.

"Tough case?"

"Yeah." She doesn't offer any more than that.

They have a strict "keep work at work" policy when it comes to their relationship. They both have incredibly taxing jobs - him as the public liaison of the FBI's Behavioral Analysis Unit, her as a star NYPD homicide detective - and it's nice to be able to leave it behind when they're together. He's her anchor, and despite them both seeing terrible things on a daily basis, he reminds her that she can be _normal._ And life can be fun.

Castle hums in her ear. "Anything I can do to help?"

"Whisk me away and make me forget?"

"If only." There's a muffled knock on his end, and Kate hears rustling, hears him greet someone, and then he's in her ear again after the click of a door. "Hey, hon, I'm sorry but I gotta go. Morgan's here."

Kate burrows deeper into the covers. "'Kay," she mumbles, the long arms of sleep already beckoning, drawing her back under. "Good luck with your case."

"You too. Talk to you later."

She thinks she manages a _you too_ before she drifts back to sleep, but just moments after hanging up her alarm starts to blare. She silences it with a groan before throwing the covers back, welcoming the cool air of her apartment.

She and Castle have only known each other for a few short months, but already she's fallen for him, harder than she's fallen for someone before. He's smart and kind, sensitive, and, despite hunting the worst of the worst for a living, makes her laugh every day. Thanks to their inconsistent schedules, and his frequent travels, they've only seen each other a couple of times since they'd met on a case his team had consulted on.

Kate sighs as she steps into the shower, standing under the hot spray for a few minutes before cleaning off the grime from the previous day. They'd been planning a weekend rendezvous in his DC apartment, but considering the lack of progress on her case, she'll likely have to cancel her trip.

She sighs again. Sometimes she hates their jobs.

* * *

"The Twelfth Precinct of the NYPD is requesting our help in the murders of two women," Castle explains to his team an hour later. "The MO's are the same, but so far they haven't found a link between the victims besides their physical similarities."

"Young, pretty, blonde. Another unsub with Mommy issues?" Prentiss pipes up, her eyes on the screen as Castle goes to the next screen of his case presentation.

"If so, he was likely abandoned by his mother, or allowed some kind of abuse to happen to him." Reid leans forward, his hands clasped on the table in front of him. "Do the women show signs of sexual abuse?"

Castle shakes his head. "None."

Reid furrows his brows. "The bodies look familiar."

"Garcia's looking for other murders with the same MO," Castle explains, "but in the meantime the NYPD wants to try and find this guy before he kills someone else. Wheels up in twenty."

* * *

"Who's that with Montgomery?" Beckett asks as she steps off the elevator. She's waiting for more information from Lanie and CSU; the crime scene had looked familiar, the blonde strangled by a rope and posed as if she was sleeping, but she can't place it.

Esposito shrugs. "Beats me, they were here when I got back."

"Hmm." Beckett squints as she studies the broad back of one of the men in her captain's office. The shoulders look familiar, his shape...when he turns enough that she can see his profile, she gasps.

Her boyfriend seems to catch sight of her from the corner of his eye, because he turns fully, and his eyes light up with the lift of his lips. She shakes her head and returns his smile with a smirk.

Before she has a chance to settle at her desk, Montgomery and Castle, along with the other agents from the BAU, step out into the bullpen. Beckett moves as close to Castle as she can without arousing suspicion. Just by being around him, she already feels her spirits lifting, despite the terrible murders he's obviously here to help solve.

"Hey everybody, listen up," Montgomery calls out, gathering everyone's attention. "As you all know, there have been two women murdered in the last two days. I called in the FBI's BAU. They helped us a few months ago with the sniper, so I felt that they would be helpful to try and catch this son of a bitch before he kills anyone else."

Kate tries to focus on her boss, and on Agent Hotchner as he explains that his team is there to help, not to take over. It's the same speech that they heard just a few months prior, so she tunes it out, keeps her eyes on Castle. She wants them to be done talking, wants to drag her boyfriend to the stairwell, just wants to be alone with him for a few minutes.

"Beckett," Montgomery says when they wrap up, "you remember Agent Castle."

She feigns innocence, and despite the glint in Castle's eye, shakes his offered hand. "I do. Nice to see you again, Agent."

He smirks. "Please, call me Castle. If you don't mind, I'll work with you."

"That's fine." Before she can suggest they retreat to the break room for coffee, and a moment alone, of course, her phone chimes with a text from Lanie.

 _911._

Castle peeks at her phone, and grabs his bag from the floor. "Where's the emergency?"

Kate just glances at him, waits for Montgomery to walk away before rolling her eyes at him. "Lanie," she explains, resisting the urge to grab his hand. "Let's go."

* * *

"I can't believe you didn't call me," she mutters in the elevator, on the way to the morgue. "A little warning would have been nice."

Castle steps closer and hooks his pinky through hers. "I wanted to surprise you," he teases, tugging lightly, chuckling when she stumbles into his side. He lets go of her hand and sneaks his hand down to press against the small of her back. "I've missed you."

She nudges him with her elbow before stepping away. "I've missed you too."

* * *

"Hey, I got that."

The mug slips from her fingers, clattering against the counter, but she stop it before it falls. She glances at Castle, a flush creeping up her cheeks as she steps to the side. "Thanks," she says, her voice quiet.

He gives her a soft smile and nudges her hip with his. "Any time." He'd bought the espresso machine for the homicide department after the first time working with them, as an anonymous gift, of course. She'd known about it, but had been sworn to secrecy.

She keeps an eye on the detectives and agents in the bullpen as she hooks a finger in his pants pocket, keeps him close. They haven't told anyone about their relationship, not until they figure out what their long term plans are, and she doesn't want to accidentally out them by cozying up to him too blatantly.

"One perfectly crafted vanilla latte, ma'am," Castle teases when he holds it towards her, and she brushes her fingers against his before taking it.

Kate closes her eyes and smiles when she inhales, the aromas of the coffee and vanilla invading her senses. "Thanks, babe," she mutters before taking a sip. The groan that escapes is completely involuntary, but it has him clenching his fists at his sides, his eyes darkening.

"Okay you need to not make noises like that," he almost growls.

She smirks. "Why?" Her tongue darts out to lick the traces of foam from her lips, and his eyes follow the movement, eyes almost black with what she can only assume is desire.

"Hey, Beckett?"

Kate steps back with a start at the sound of Ryan's voice as Castle turns to face the counter, presumably to calm himself down. "What's up, Ryan?"

Ryan glances between the two of them, then blinks a few times and seems to shakes his head. "We got a lead."

* * *

She doesn't worry that Ryan and Castle haven't returned from Jerry Tyson's hotel room. Not until an hour and a half have passed. At two hours she starts to pace in the break room. She and Castle have plans, plans that include minimal clothing, and she doubts that he'd blow that off.

"Yo, Beckett, you okay?"

She drops her phone when Espo startles her, and she bends to pick it up and feels her face flush with embarrassment. "I don't know. I assumed they'd be back by now." She nods towards Castle's team, who are busy packing up. "Any word from Castle? Or Ryan?" she adds when Espo quirks an eyebrow.

"Maybe they went out for a cold one before he leaves. You know, there's this thing called 'celebrating a win,'" he teases.

Beckett just gives him a look. He could be right. But she fires of a text to Castle anyway, asking him to call, and continues to pace.

When twenty more minutes pass with no response, she approaches the rest of the BAU. "Hey, have you guys heard from Castle or Ryan?"

Prentiss glances at the others, who offer shakes of their heads. "No, not yet. You haven't either?"

"No." Kate checks her phone one more time before grabbing her coat. "I don't like this. I'm going to the hotel."

"You know what doesn't make sense to me?" Morgan asks as they all slip their coats on. "Why Paul McCardle's operation happened just now. Gates has been out of prison for a month."

"Gates needed him for the murders," Reid points out as they get in the elevator. "It wouldn't have worked if McCardle was in recovery."

Kate drives separately to the hotel, her mind racing the whole way. Castle and Ryan were supposed to tell Tyson that Gates had been arrested, and that he could go home. It should have taken an hour, tops. And despite their plans, Castle would have at least checked in with his team, even if he hadn't wanted to call her directly with Ryan there.

Jerry Tyson is 3XK.

It's the only thing that makes sense.

She presses down on the accelerator even harder, Morgan behind her keeping pace. If Tyson is the Triple Killer, and neither Castle nor Ryan realizes it…

 _Shit._

* * *

"Tyson's gone," Castle calls out as soon as Beckett kicks the door in. "He has our badges and guns. Ryan needs an ambulance."

"No I don't."

Kate lets the others sweep the room as she holsters her gun and unties Castle. "I'm so glad you're okay," she whispers, her lips inches from his neck. She brushes her fingers against his as she untangles the rope from his wrists, but she steps away when he stands, shoves her hands in her back pockets to resist the urge to pull him into a hug.

Castle's fingers clench at his side in obvious restraint, and he sits on the bed willingly when a paramedic prods him to. "Me too. How'd you figure it out?"

Prentiss motions towards Beckett. "She figured it out first when you guys didn't return."

Castle gives Kate a crooked smile. "Thanks."

Although the rest of the team flies back to DC that night, Castle pleads his case to stay in New York one more night. He claims it's to see his mother, but the knowing look he gives Kate tells her it's not.

Later, as she lies in his arms, their limbs a tangled mess, she can't stop the tear that falls on his naked chest.

"Hey," he says quietly, curling his fingers under her jaw. "What's wrong?"

Kate lifts her face in a silent request for a kiss, to which he complies with the crane of his neck. "I just," she sighs against his mouth, "I'm glad you're okay." She hums when his arms tighten around her. "I don't know what I would have done if he'd…" She trails off, not even wanting to say what had crossed her mind.

Castle shifts to his side and faces her, runs one hand up her waist to cup her jaw. "I'm not going anywhere," he assures her, his thumb teasing the corner of her mouth. "You're stuck with me, Kate."

Kate catches the tip of his thumb with her teeth, watches his eyes darken as she soothes the sting with the touch of her tongue. She captures his low growl with her mouth and even as he trails his lips down her neck, she arches into him.

"I love you," she gasps, and when he freezes, she immediately regrets saying the words out loud.

Her mind races while she waits for Castle's reaction. They've only known each other a few months, and even though she hadn't been with anyone else since their initial passion-filled night together, had been official for just half that. But never before has she felt a connection, a desire to be with someone like she does with Castle. And because of their no-work-talk policy, she knows they work well together on a personal level, as well as physical.

And the worry she felt earlier, the sick feeling in her stomach when she thought he might have become a victim of Jerry Tyson, was the last piece of the puzzle.

She loves him. Desperately.

Castle abandons her neck and hovers over her once again, his expression unreadable.

"I know it's soon," she stammers, "and if you don't feel it I get it, but I wanted you to kn-"

He cuts her off with his mouth, his tongue teasing, sweeping against hers in a kiss that leaves her breathless. His lips quirk in a smile when they part. "I love you too, Kate," he husks, sending shivers down her spine.

"Yeah?"

He chuckles. "Yeah."

"Hmm." Kate threads her fingers through his hair and pulls him down for another kiss. "Show me."

* * *

What neither of them know is that on the short plane ride back to DC, Castle's entire team, including Hotch and Garcia, place bets on how long before Castle and Beckett make their relationship public.

When Castle announces that Kate is pregnant just ten weeks later, the only surprise among them is that Reid wins the pool.

* * *

 **-FIN-**

* * *

 _A/N 2: For Rachel, I am grateful every day that you're in my life. Happy belated birthday, lovely!_

 _A/N 3: As usual, thanks to Callie for her beta._


End file.
